PERFECT FOR MEDIUM SIZED DOGS: This collar is 1 inch wide and adjusts to fit dog neck sizes of 13 inches to 18 inches. This makes the sizing perfect for medium breeds of dog. SIZING INSTRUCTIONS: To determine collar size, please measure your dog’s neck with a sewing tape or string. That size will be the neck size you need. The collar sizes listed are the range of neck sizes that the collar will fit. GUARANTEED FOR LIFE: Each collar is made out of the highest quality materials and has a lifetime guarantee. CUSTOMIZABLE: Made with the trademark ScruffTag nameplate, the built-in ID tag holds the most important information right on the 'scruff' of your dog’s neck. This makes it easy to identify the dog and get it back home. Each nameplate is laser engraved using a high power fiber laser with up to 4 lines of text in your choice of 11 fonts. HIGH QUALITY: This collar is made in the USA from durable, fade-resistant nylon webbing. This webbing is strong but super soft to the touch. All hardware is made from corrosion-proof stainless steel hardware.